Method and apparatus to thwart bit balling of drill bits

ABSTRACT

Disclosed herein is a drill bit. The drill bit includes, a body of the drill bit having at least two blades defining a junk slot therebetween, at least one cutter positioned on at least one of the at least two blades, and at least one diverter positioned downstream of the at least one cutter defined by a direction of travel of the cuttings, the at least one diverter configured to divert cuttings to travel along a trajectory more parallel to a profile of the junk slot.

BACKGROUND

Typical drill bits for drilling wellbores into earth formations includea plurality of blades defining junk slots therebetween for routing andsubsequent removal of cuttings cut by cutters attached to the blades.When the junk slots become clogged and no longer effectively evacuatecuttings freely, a condition known as bit balling may occur whichresults in a reduction in the rate of penetration of the drillingoperation. Methods and apparatuses that thwart bit balling of drill bitswould be well received in the industry.

BRIEF DESCRIPTION

Disclosed herein is a drill bit. The drill bit includes, a body of thedrill bit having at least two blades defining a junk slot therebetween,at least one cutter positioned on at least one of the at least twoblades, and at least one diverter positioned downstream of the at leastone cutter defined by a direction of travel of the cuttings, the atleast one diverter configured to divert cuttings to travel along atrajectory more parallel to a profile of the junk slot.

Further disclosed herein is a method of routing cuttings through a junkslot of a drill bit while drilling. The method includes, positioning atleast one diverter downstream of at least one cutter and upstream of ajunk slot, and altering a direction of travel of cuttings cut by the atleast one cutter to increase an angle of incidence with a profile of thejunk slot.

Further disclosed herein is a drill bit cuttings diverter. The diverterincludes, a surface positioned substantially between at least one cutterand a junk slot profile of a drill bit, the surface is configured toincrease an angle of incidence between a trajectory of the cuttings andthe junk slot profile.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way.With reference to the accompanying drawings, like elements are numberedalike:

FIG. 1 depicts a partial cross-sectional view of a drill bit disclosedherein;

FIG. 2 depicts a partial perspective view of the drill bit of FIG. 1;and

FIG. 3 depicts a partial cross-sectional view of an alternate drill bitdisclosed herein.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosedapparatus and method are presented herein by way of exemplification andnot limitation with reference to the Figures.

Referring to FIGS. 1 and 2, an embodiment of a partial view of a bitballing resistant drill bit disclosed herein is illustrated generally at10. The drill bit 10 includes, a body 12 having a plurality of blades 14(one of which is shown), a plurality of cutters 18, a junk slot 22, andthree cuttings diverters 26. Without the cuttings diverters 26, cuttingscut by the cutters 18 tend to travel in a direction normal to a surfacethe formation 30 being cut. For example, cuttings cut by the cutter 18Atend to travel in a direction along arrow 34. The cuttings continuesubstantially along this trajectory until they impact a junk slotprofile 38, typically at a very shallow angle of incidence 42.Consequently, the cuttings need to significantly change direction totravel along arrow 46, for example, to be evacuated through the junkslot 22 or clogging of the junk slot 22 may occur resulting in what iscommonly known as bit balling. Consequently, the arrow 46 trajectory issubstantially directed radially outwardly.

The cuttings diverters 26 disclosed herein are positioned downstreamfrom the cutters 18, as defined by the flow of cuttings cut by thecutters 18. The cuttings diverters 26 are oriented in such a way as topresent a surface 50 that is configured to be contacted by the movingcuttings. Cuttings that contact the cuttings diverters 26 will changedirection to a direction, for example, along arrow 54, whichsignificantly increases the angle of incidence 42 with the junk slotprofile 38. This redirection may be enough to keep the cuttings fromimpacting the junk slot profile 38 completely. Regardless of whether thecuttings impact the junk slot profile 38, the cuttings diverters 26, indirecting the cuttings to a path more parallel to the junk slot profile38, encourage the cuttings, and other material positioned within thejunk slot 22, to keep moving through the junk slot 22, therebydecreasing the likelihood of balling within that junk slot.

In this embodiment, the surface 50 of the cuttings diverters 26 iscurved, although non-curved surfaces can also be used. The curvature issuch that an amount of redirection of cuttings contacting the surface 50increases the further the cuttings move along the surface 50. Thisvarying of angle of the curved surface 50 allows the cuttings to contactthe surface 50 at a shallow angle 56 that is less likely to abrade thesurface 50 than configurations having greater angles 56.

The cuttings diverters 26 in this embodiment are attached to a wall 58of the blade 14. Attachment of the cuttings diverters 26 to the wall 58can be through one of a variety of mechanisms including, welding,brazing, fastening, adhesively bonding, and integrally formingtherewith, for example. And the diverters 26 can be made of a variety ofmaterials including metal, ceramic and polymer, for example, andfabricated by known processes such as machining and molding. The shapesof each of the cuttings diverters 26 can be different from one another.Additionally, the cuttings diverters 26 can have features designed tointeract with one or more of the other cuttings diverters 26. Forexample, the cuttings diverter 26B has a ramped face 62 that blends withthe wall 58 at a first end 66 and protrudes a distance from the wall 58at a second end 70 by perhaps ⅛ to ½ of an inch. The ramped face 62forces cuttings exiting the cuttings diverter 26A away from the wall 58,thereby decreasing friction between cuttings and the wall 58 that couldotherwise contribute to bit balling.

Embodiments may include any number of cuttings diverters 26, with theactual number, size and shape of the cuttings diverters 26 beingselected in accordance with the needs of particular applications. Theseneeds being influenced by such things as, downhole conditions, formationstructure and drill bit design, for example. As such, some drill bitsmay have a separate cuttings diverter in operable communication witheach cutter, while other drill bits may have cuttings diverters that arein operable communication with more than one cutter.

Referring to FIG. 3, an alternate embodiment of a drill bit 110disclosed herein is illustrated. The drill bit 110 includes, a blade114, with cutters 118 attached thereto, a junk slot 122 and cuttingsdiverters 126. A primary difference between the drill bit 10 and thedrill bit 110 is the positioning of the cuttings diverters 126. Thecuttings diverters 126 are positioned further from the cutters 118, andare attached to a body 128 of the drill bit 110 at an intersection of awall 158 of the blade 14 and a junk slot profile 138. Such a positioningof the cuttings diverters 126 can make them easier to form as anintegral part of the body 128. Additionally, the cuttings diverters 126have non-curved surfaces 130 with angles that vary according to thecutter 118 that each cuttings diverter 126 is in operable communicationwith.

While the invention has been described with reference to an exemplaryembodiment or embodiments, it will be understood by those skilled in theart that various changes may be made and equivalents may be substitutedfor elements thereof without departing from the scope of the invention.In addition, many modifications may be made to adapt a particularsituation or material to the teachings of the invention withoutdeparting from the essential scope thereof. Therefore, it is intendedthat the invention not be limited to the particular embodiment disclosedas the best mode contemplated for carrying out this invention, but thatthe invention will include all embodiments falling within the scope ofthe claims. Also, in the drawings and the description, there have beendisclosed exemplary embodiments of the invention and, although specificterms may have been employed, they are unless otherwise stated used in ageneric and descriptive sense only and not for purposes of limitation,the scope of the invention therefore not being so limited. Moreover, theuse of the terms first, second, etc. do not denote any order orimportance, but rather the terms first, second, etc. are used todistinguish one element from another. Furthermore, the use of the termsa, an, etc. do not denote a limitation of quantity, but rather denotethe presence of at least one of the referenced item.

1. A drill bit, comprising: a body of the drill bit having at least twoblades defining a junk slot therebetween; at least one cutter positionedon at least one of the at least two blades; and at least one diverterpositioned downstream of the at least one cutter defined by a directionof travel of the cuttings, the at least one diverter configured todivert cuttings to travel along a trajectory more parallel to a profileof the junk slot.
 2. The drill bit of claim 1, wherein the at least onediverter is attached to one of the at least two blades.
 3. The drill bitof claim 1, wherein the at least one diverter is attached the profile ofthe junk slot.
 4. The drill bit of claim 1, wherein the at least onediverter is attached to the body by one selected from the groupconsisting of welding, brazing, fastening, adhesively bonding andintegrally forming with the body.
 5. The drill bit of claim 1, whereinthe at least one diverter is configured to divert cuttings radiallyoutwardly of a rotational axis of the drill bit.
 6. The drill bit ofclaim 1, wherein the at least one diverter is configured to divertcuttings away from a wall of the at least two blades.
 7. The drill bitof claim 1, wherein the at least one diverter extends from a surface ofone of the at least two blades by ⅛ to ½ inch.
 8. The drill bit of claim1, wherein the at least one diverter is configured to divert cuttings totravel in a direction more parallel to the profile of the junk slot. 9.The drill bit of claim 1, wherein a surface of the diverter is curved.10. The drill bit of claim 9, wherein curvature of the surface increasesa redirection of cuttings contacting therewith as the cuttings movealong the surface.
 11. The drill bit of claim 1, wherein a surface ofthe diverter is non-curved and angled in relation to the cutter.
 12. Thedrill bit of claim 1, wherein each of the at least one diverter is inoperable communication with the at least one cutter.
 13. The drill bitof claim 1, wherein the at least one diverter is selected from the groupconsisting of metal, ceramic and polymer.
 14. The drill bit of claim 1,wherein the at least one diverter is a polymer fabricated by molding.15. The drill bit of claim 1, wherein the trajectory is radiallyoutwardly.
 16. A method of routing cuttings through a junk slot of adrill bit while drilling, comprising: positioning at least one diverterdownstream of at least one cutter and upstream of a junk slot; andaltering a direction of travel of cuttings cut by the at least onecutter to increase an angle of incidence with a profile of the junkslot.
 17. The method of routing cuttings through a junk slot of a drillbit while drilling of claim 16, wherein the altering a direction oftravel of cuttings includes contacting the at least one diverter withthe cuttings.
 18. The method of routing cuttings through a junk slot ofa drill bit while drilling of claim 16, wherein the altering a directionof travel of cuttings includes aligning a trajectory of the cuttingswith a desired flow path through the junk slot.
 19. A drill bit cuttingsdiverter, comprising a surface positioned substantially between at leastone cutter and a junk slot profile of a drill bit, the surface beingconfigured to increase an angle of incidence between a trajectory of thecuttings and the junk slot profile.
 20. The drill bit cuttings diverterof claim 19, wherein the surface is curved.
 21. The drill bit cuttingsdiverter of claim 19, wherein the surface is attached to a body of thedrill bit.
 22. The drill bit cuttings diverter of claim 19, wherein thesurface is integral with a body of the drill bit.